This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
UPnP technology defines an architecture for pervasive peer-to-peer network connectivity of intelligent appliances, wireless devices, and personal computers of all form factors. UPnP technology is designed to bring easy-to-use, flexible, standards-based connectivity to ad-hoc or unmanaged networks whether in the home, in a small business, in public spaces, or attached to the Internet. UPnP technology provides a distributed, open networking architecture that leverages TCP/IP and Web technologies to enable seamless proximity networking in addition to control and data transfer among networked devices.
The UPnP Device Architecture (UDA) is designed to support zero-configuration, “invisible” networking and automatic discovery for a breadth of device categories from a wide range of vendors. With the UDA a device can dynamically join a network, obtain an IP address, convey its capabilities, and learn about the presence and capabilities of other devices.
Remote Access enables remote UPnP devices to interact with the UPnP devices located in a home network, as they are physically attached to the home network. Typically, the remote device connects to the home network using a secure tunnel such as the tunnel provided by IP security (IPsec) technology. A simple service discovery protocol (SSDP) proxy in the home network interacts with the remote device and provides several functionalities in discovery of services provided by home network devices. For example, the SSDP proxy maintains a list of local devices/services that can be discovered, forwards search/notify requests, filters multicast messages, etc.
A number of systems have been developed involving the creation of “virtual devices,” but each has its drawbacks. One such system comprises a UPnP relay tool that is based upon the idea of bridging two UPnP networks by creating a virtual device in one network for each device in the other network. However, this approach is very complex and requires software to run on a personal computer. This system is not scalable because, as new services/functionalities are added in the UPnP stack, the relay tool must be updated on both sides of the UPnP network. U.S. Application Publication No. 2004/0233904 describes a mirroring agent that is similar to the virtual device described above. This mirroring agent also possess the same shortcomings as the virtual agent.
The concept of virtual devices is described by the Digital Living Network Alliance, an alliance of leading companies in the consumer electronics, mobile and personal computer industries. Virtual devices are described as bridging the mobile handheld domain and the fixed network domain. The roles of the virtual devices are to offer transcoding, transcaling, transrating services between the two domains as they don't share common codecs. However, no such support currently exists at the UPnP stack of network protocols.